Weight Converter

What this tool does

Weight Converter changes a mass between metric, imperial, US, troy and traditional Indian units. Every conversion uses the legal definition of the pound (0.45359237 kg) and related exact factors, and you can convert a whole column of values at once.

Mass is quoted in different units depending on who is talking. A UK doctor may record body weight in stone, a US recipe lists ounces, a jeweller weighs gold in troy ounces or tola, and shipping invoices use kilograms or tonnes. Guessing the conversion, or using the wrong kind of ounce, leads to wrong doses, wrong postage and wrong prices.

This converter routes every value through the kilogram using exact definitions: the avoirdupois pound is 0.45359237 kg, an ounce is one sixteenth of that, a stone is 14 pounds, and the grain is 64.79891 mg. Troy ounces (480 grains), pennyweights, metric carats (200 mg) and the tola (180 grains, about 11.66 g) are derived from those same constants, so the figures agree with official tables. Everything runs locally in your browser.

How to use Weight Converter

1. Enter the amount in the Value field.
2. Choose the unit you have in From and the unit you need in To.
3. Read the Result and copy it with the copy icon, or press the swap button to reverse the direction.
4. Move the Decimal places slider to show more or fewer digits.
5. Scan the table to see the same weight in every unit at once.
6. For many values, paste a column into Batch convert and download the results as CSV.

Tips for better results

• A quick mental check: 1 kg is a little over 2.2 lb, so 70 kg is roughly 154 lb.
• To express a body weight like 11 st 4 lb, convert 11 stone and 4 pounds separately and add the kilograms.
• When pricing gold or silver, use troy ounces; a troy ounce is 31.1035 g while an ordinary ounce is 28.3495 g.
• Quintal (100 kg) is the usual unit for crop yields and grain prices in India.

Common use cases

• Converting body weight between kilograms, pounds and stone for fitness apps and medical forms.
• Checking parcel weights against courier limits given in kg or lb.
• Converting gold rates between grams, tola and troy ounces.
• Scaling ingredient weights in imported recipes from ounces to grams.

Common mistakes to avoid

• Using a troy ounce where an avoirdupois ounce is meant, or the other way round, which introduces an error of about 10%.
• Confusing the metric tonne (1,000 kg) with the US short ton (907.18 kg) or the UK long ton (1,016.05 kg).
• Treating fluid ounces, which measure volume, as if they were ounces of weight.
• Mixing up the carat of gemstone mass (200 mg) with the karat that describes gold purity.